This invention relates to an apparatus for automatically inserting semiconductor devices or electronic parts with pins such as integrated circuits, semiconductor elements, resistors, capacitors and the like into holes formed in a printed circuit borad at predetermined positions.
Various kinds of electronic circuit elements with pins such as semiconductor devices have hitherto been charged in a printed circuit board by hand, but manual operations for selecting predetermined electronic parts, correcting the shape and position of pins and inserting the pins into predetermined holes of the printed circuit board are very troublesome and the operation efficiency is very low. The number of assemblies made by a single worker per day is therefore limited to a smaller number and the considerably increasing demand cannot be supplied anymore. For the above reason, an apparatus for automatically inserting semiconductor devices or electronic parts with pins into the printed circuit board has been developed and put to practical use. For example, there has been developed an apparatus for automatically inserting ICs by setting particular addresses at IC charging positions on a printed circuit board with the use of a computer. In this known automatic IC insereter, data for controlling the operation of the apparatus must be provided by means of a tape from the outside and thus there are many disadvantages in that preparation work for forming a programme is complicated, a change of the programme is not easy and the inserter itself is very difficult to handle in practice. In addition, since the addresses at the IC inserting positions on the printed circuit board are fixed, insertion becomes impossible if the position of the board is shifted even slightly with respect to an inserting head. As a countermeasure therefor, two reference holes are bored in the printed circuit board and a pair of projections are provided on a table, and when the printed circuit board is set on the table correctly, the projections are inserted into the reference holes. Such a method takes additional time, and operations for forming the reference holes on the printed circuit board and troublesome detachment of the printed circuit board from the table are encountered. In this connection, it should be noted that in the known inserter, the insertion and detachment of the board with respect to the table are not automatically but manually operated by workers. It is further proposed to make the diameter of the IC pin inserting holes in the board larger than the width of the pins to some extent in order to absorb the positional error between the holes and the table, but if the inserting hole is made too large, the pins might not be soldered firmly and this results in unstable electrical connections. There is hence a limitation on the diameter of the holes.
The other prior automatic insertor employs a copying system in order to overcome the above disadvantages to some measure, so as to save time required for forming a programme and to deal with any change promptly and easily. But, in this known inserter, pins are not precisely corrected (or shaped), so that the rate of proper insertion is low, such as 90 to 95%, and inferior goods are frequently produced. Morever, the above disadvantage about positioning of the printed circuit board to the table is not solved yet. As to correction or shaping of an IC pin, when the pin is inserted into the hole of the printed circuit board, the pin is gripped, bent inward and inserted into the hole, and as a result, the pin cannot be inserted if the pin is originally bent too far inward or if it is bent in a lateral direction. In addition, the pin is cut only after insertion into the hole of the printed circuit board.
Further, in the above-described prior IC insertor, rail-like cassettes storing a number of ICs of the same kind in a row are arranged along an inclined guide in the perpendicular direction, but the number of ICs stored in one cassette is comparatively small, such as 24. It is often necessary to exchange an empty cassette with a new cassette filled with ICs, so that operation is burdensome. In order to remove such disadvantage, one might consider juxtaposing a pluarlity of cassettes filled with ICs of the same kind, but this would produce another disadvantage in that the whole apparatus would become large and difficult to operate. Such disadvantages become more prominent when the kind of ICs to be inserted into the printed circuit board is increased.